NHTSA Complaint #11436876 — 2016 GMC SIERRA 2500

I keep getting a warning message "service trailer brake system". The warning may come on for a second or it may stay on for 10 to 15 minutes. It may do it once a month or 10 times in a 2 minute period. Whenever this happens I lose the electrical braking system on what I am towing. There is no set pattern or circumstance for when or how long it will happen. I was told if the alert is not on there is not a way to diagnose the problem and since I never know when it will happen I cannot schedule any type of diagnostic service. It does seem to happen more often when it is raining but has happened in perfect weather too. The warning has occurred both when I am towing and when I am not. I've done searches for possible causes and it seems to be a common problem. I regularly tow a 12,000 lb. fifth wheel RV with my family. I cannot afford to lose my ability to stop in a reasonable amount of time. I simply cannot do it when I lose my trailer braking system. The date below is the last incident.